JP 2003-81549 A discloses an elevator car position detecting device which, for detecting the position of a car within a hoistway, detects the position of the car by measuring the RPM of a pulley around which a steel tape that moves together with the car is wound. The pulley is provided with a rotary encoder that outputs the RPM of the pulley in the form of a pulse signal. The pulse signal from the rotary encoder is inputted to a position determining portion. The position determining portion determines the position of the car based on the input of the pulse signal.
In the elevator car position detecting device as described above, however, once slippage occurs between the rope and the pulley, the rotation amount of the pulley no longer coincides with the travel distance of the car, so a deviation occurs between the car position as determined by the position determining portion and the actual car position. As a result, the operation of an elevator is controlled on the basis of an erroneous car position that is different from the actual car position, so there is a fear of the car coming into collision with the lower end portion of the hoistway.